The invention relates to a self-locking screwing attachment device (1a, 1b) including a nut (2a, 2b) screwed onto a threaded tip (3a, 3b) extending in a screwing axis (X), characterized in that the nut (2a, 2b) includes: a first element (6a, 6b) rotating relative to the tip (3a, 3b) when screwing; a second element (13a, 13b) rotatably engaged with the tip (3b) or an adjacent part (5) to be assembled, the tip (3a) passing therethrough; a stop member (23a, 23b) rotatably secured to the first element (6a, 6b); a releasable coupling means (26a, 26b, 27a, 27b, 28a, 28b) between the stop member (23a, 23b) and the second element (13a, 13b), the nut also being provided with an area for direct clamping between a first clamping surface (20a, 20b) of the first element (6a, 6b) and a second clamping surface (21a, 21b) of the second element (13a, 13b), when the second element (13a, 13b) axially engages with the tip (3a, 3b) or said adjacent part (5) to be assembled.